The art of oral hygiene devices is replete with multi-headed brush elements. For example, the concepts of dual and/or triple brush heads disposed on the same end of a handle and in which at least two such brush heads are disposed in generally opposing relationship to each other are shown, inter alia in Ruff (U.S. Pat. No. 1,679,946), Genn (U.S. Pat. No. 1,830,995), Davis (U.S. Pat. No. 1,908,509), Dinhofer (U.S. Pat. No. 2,807,820), Froidevaux (U.S. Pat. No. 3,953,907), Weiss (U.S. Pat. No. 4,498,209), Hegemann (U.S. Pat No. 5,305,491), Klinkhammer (U.S. Pat. No. 5,316,027), and Mak (UK Patent Application GB 2192784 A).
The prior devices have been manufactured in a plurality of manners. For example, some prior devices have integrally formed opposing arms and brush heads. Davis and Froidevaux disclose such devices. At least one manufacturing difficulty occurs with integrally formed opposing arms and heads in that it is not a simple task to implant the bristles on the opposing heads and thereafter also trim the bristles to the proper shape and height.
As an alternative to integral formation, Ruff teaches two separate spring handles which are uniquely pivoted together through use of an elliptical member on one handle inserted in a corresponding elliptical slot defined in the other handle, the handles then being pivoted relative to each other to hold the handles and brush heads in opposed relationship.
In another alternative, Genn teaches the production of a device in which two U-shaped springs are molded and imbedded in the opposing brush heads and are fastened to the toothbrush handle by means of cement or riveting.
Dinhofer teaches an initially flat, highly flexible main body in which at least two sets of bristles are imbedded. Then, the main body is bent and attached to the handle so that the two sets of bristles are ultimately disposed in opposing relationship.
In Froidevaux, the primary embodiment involves the separate manufacture of two handle portions which are ultimately connected together by an elongated dovetail joint. Each handle portion has a separate head so that when fully assembled, the resulting toothbrush has two opposing heads.
Weiss also involves the preliminary manufacture of separate handle members each having a brush head at one end thereof. These handle members are then joined at the non-brush head ends by a flexible pivot means such as a metal wire or flexible plastic.
Hegemann teaches the manufacture of a triple headed brush in which the three brush heads are independently attached to a single handle preferably using a snap fit of interlocking mechanical members. Other methods of connecting the three brush heads are also taught including using adhesive bonding, press pins, clamps, and/or sleeves, inter alia.
In Klinkhammer, two opposing arms are first integrally formed with and on one end of a handle. Then, two bristled tooth brushing members are subsequently attached one each to each of the respective ends of the opposing arms. The brushes are preferably molded around the pre-formed ends of the opposing arms using a different molding material for the different properties needed for the brushes.
Mak teaches a toothbrush with separately manufactured arms. These arms are subsequently inserted into a socket or sockets at one end of the handle and held in place by a variety of disclosed methods, preferably including a deflectable detent member such as a deflectable finger or a spring loaded ball. The arms are, however, preferably moveable such that they are rotatable relative to the handle. Thus, the brush heads may be moved to an opposing relationship relative to each other as well as to a position in which the two heads face in generally the same direction.
In view of the foregoing, it is readily apparent that there are many methods for manufacturing oral care devices having multiple heads at one end of a handle. However, many difficulties remain. For example, as related in Hegemann it is difficult to use conventional, or even special machinery to implant, trim and polish bristles in generally opposing brush heads. Moreover, the numerous highly complicated arm and handle connections are also not easily achievable using conventional machinery. Further, the use of mechanical bands and/or adhesives allows for spatial pockets to remain between component parts which provide areas for bacteria to live and grow. The use of adhesives is also not reliable against breakage, and adhesives further require intensive labor during assembly. It is toward the elimination of these and other manufacturing difficulties that the present invention is directed.